In recent years, with the continuous improvement of the level of modernization, electronic equipment and computer equipment installed in civilian buildings are more and more. The electronic information devices generally work in lower operating voltage, the voltage withstand level is also very low, which is extremely vulnerable to lightning electromagnetic pulsehazards. Therefore, the civil buildings with information systems equipment should consider lightning electromagnetic pulse protection measures in addition to preventing lightning directly stroke measures. Establishing perfect lightning surge protective device is an important part of the design of electrical engineering. This paper proposes how to install surge protector according to different forms of low-voltage power supply system and notes in practical engineering, which can be reference for engineering design staff in practical applications.
Notes for Surge Protector Installation
(1) The first level protective SPD should be located close to the total potential connection terminals of the home line of buildings; the second and third protected SPD should be installed as close as possible to the protected equipment.
(2) The wire of
connected to equipotential connection should be as short as possible and straight.
(3) To meet the tolerated energy requirements of information system equipment, the installation of the SPD can carry out multi-level co-ordination. Energy cooperation between the SPD should be considered during the multi-level co-ordination, the decoupling device should be cascaded when there is freewheeling in the line. It's better to adopt the similar cable surge protector products from the same manufacturers if the condition allows and you should require manufacturers to provide the installation distance requirements between all levels. If it is unable to obtain accurate data, the decoupling device should be connected when the line length between the voltage switching and voltage limiting type SPD is less than 10 meters and the length between and pressure limiting type SPD is less than five meters.
(4) In the same power system, when the SPD protection voltage level installed at the beginning of the power supply device Up ≤ 50% end of the voltage level of the protective equipment, you may simply install a surge protector.
(5) You must consider the impact of overcurrent or ground fault on information system equipment running that may produced by the degradation or the end of life. So the overcurrent protection device should be installed by the supply side of the SPD (such as fuses or air circuit breaker), overcurrent protection (set inside or outside), to assume equal to and greater expected maximum short-circuit current than the installation together with SPD. You should consider that their products should have the maximum overcurrent protector which is specified by the SPD manufacturer when you select. In addition, SPD rated blocking flow accumulator value specified by the manufacturers should not be less than the expected short-circuit current at the installation. Residual current protection device should be installed in the TT system, and should be with the deterioration display functions.
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